This invention relates generally to a pump apparatus for pumping plural fluids at varying pressures. More specifically, the invention is directed to a pump apparatus for pumping plural fluids at varying high and low pressures. Multiple pumps for pumping a plurality of liquids are known in the prior art. An example of such a pump is shown in U.S. Pat. No. 3,260,211. Also, multiple piston or plunger pumps have previously been used with their pistons or plungers serially connected so as to provide a single high pressure output. An example of a plural cylinder pump is shown in U.S. Pat. No. 3,163,121.
So far as known, it has been a practice in the past to provide even intervals between the compression strokes of multiple plunger pumps. This has been previously done by providing a single drive shaft for a pump and either through the use of a crank or cams evenly dividing the intervals between the strokes of each piston for each revolution of the drive shaft. Such an application has been previously used for pumping a liquid into a single output stream.